1. Field of the Invention
The present invention relates to a sheet feeding apparatus and an image forming apparatus and, more particularly, to a construction for positioning a regulating member to regulate the position of a sheet.
2. Description of the Related Art
Recently, in an image forming apparatus such as a printer or a copying machine, the one in which a sheet is fed to an image forming portion to form an image has been widely marketed. Furthermore, as such an image forming apparatus, typically a sheet feeding cassette is removably mounted onto an image forming apparatus main body, and a sheet that is contained in the sheet feeding cassette is automatically fed to the image forming portion by the sheet feeding apparatus.
As such a sheet feeding cassette for use in such an image forming apparatus, there is a universal cassette in which various sizes of sheets can be contained in the same cassette. In a sheet containing portion of this universal cassette, there is movably provided a trailing edge regulating member regulating a trailing edge of a sheet in a feeding direction of the sheet that is contained in the sheet containing portion. Furthermore, there is provided movably a side edge regulating member regulating a side edge of the sheet in a width direction orthogonal to the feeding direction of the sheet. Then, by moving the trailing edge regulating member and the side edge regulating member in alignment with the trailing edge and the side edge of a sheet to be contained to regulate the position of the side edge and the trailing edge of the sheet, various sizes of sheets can be contained.
Moreover, in such a universal cassette, by regulating the side edge of the sheet with the side edge regulating member, as well as by regulating the trailing edge with the trailing edge regulating member, a leading edge position of the sheet is to be set in a predetermined position at all times. Whereby, regardless of the size of a sheet, a stable feed of the sheet can be conducted.
In the meantime, when a universal cassette is mounted or dismounted with respect to an image forming apparatus main body, there are some cases where due to an inertial force of a sheet or an impact that is generated by mounting/dismounting operation, these regulating members are moved from a standard sheet regulated position. Furthermore, when the regulating member is moved in such a way, the state in which the sheet cannot be held in a standard position occurs, and thus failures such as a faulty feed, skew feed, and double feed of sheets are made to occur at the time of feed operation.
Thus, conventionally, for example, there has been a universal cassette in which a rack is provided at a cassette main body, as well as a stopper is provided at a regulating member; and by the engagement of the stopper with the rack, the regulating member is secured. Incidentally, in this universal cassette, the regulating member is released from being secured by disengaging the stopper with the use of a release lever that is disposed protruding from an outer wall of the regulating member. This art is described in Japanese Patent Application Laid-Open No. 2001-88948.
Incidentally, in such a conventional universal cassette, in the case where a regulating member is secured with a rack and a stopper, this method is effective with respect to the collision at the time of mounting or dismounting the cassette or the impact at the time of distribution. In addition, due to that the release lever for releasing the engagement of the stopper is disposed protruding from the outer wall of the regulating member, a positional adjustment of the regulating member can be made even in the state in which the sheets are stacked in the cassette, thus resulting in a high operability.
In the meantime, as to this release lever, for example, in the case where the regulating member is moved in a direction of regulating a sheet of a small size (hereinafter referred to as a smaller size regulation direction), when the release lever is pressed in the smaller size regulation direction, the engagement of a stopper will be released. On the other hand, in the case where the regulating member is moved in a direction of regulating a sheet of a large size (hereinafter referred to as a larger size regulation direction), the release lever needs to be once grubbed to release the engagement of the stopper with the rack.
That is, conventionally, in the case where the regulating member is moved in the smaller size regulation direction, when the release lever is pressed in the smaller size regulation direction, the engagement of the stopper is automatically released. However, in the case where the regulating member is moved in the larger size regulation direction, to release the engagement of the stopper, operation of grubbing the release lever needs to be done, and thus the ease of operation is impaired.